1. Field of the Invention
The present invention relates to a method for producing reflectors used in reflective liquid crystal display devices and the like, and liquid crystal display devices equipped with such reflectors.
2. Description of the Prior Art
Liquid crystal display devices have been widely used, since they can be produced as small, light-weight, and thin display devices. In particular, reflective liquid crystal display devices equipped with a reflective plate have taken attention because of their reduced electric-power consumption.
FIG. 12 shows the structure of a reflective liquid crystal display device of the prior art. This reflective liquid crystal display device A is composed of: a pair of transparent substrates 1 and 2 opposing each other; a liquid crystal layer 4 encapsulated between the pair of transparent substrates 1 and 2 by a sealing member 3; a polarizing plate 6, phase-contrast plates 7 and 8 formed on the top side of the transparent substrate 1 in that order from the top; and a reflector 10 formed on the bottom side of the transparent substrate 2. The reflector 10 is composed of: a glass substrate 51 having an uneven pattern 51a formed on the top side thereof; an Al reflective film 52 provided on the glass substrate 51, and a sticky layer 53 formed on the Al reflective film 52. An electrode layer 15 made of ITO, a top-coat layer 16, and an alignment film 17 are formed on the bottom side of the transparent substrate 1 in that order from the top. A color filter layer 18 required for color displaying, an over-coat layer 19, an electrode layer 20, and an alignment film 54 are formed on the top side of the lower transparent substrate 2 in that order from the bottom.
According to the reflective liquid crystal display device A having the above-mentioned structure, the incident light coming from the upper side of the transparent substrate 1 is transmitted through the liquid crystal layer 4, reflected by the reflective film 52, re-transmitted through the liquid crystal layer 4, and passes through the transparent substrate 1. The polarization direction of the light is controlled according to the alignment of the liquid crystal layer 4, and a bright state and a dark state of the display device can be switched by allowing or not allowing the reflected light to pass through the polarizing plate 6. The uneven pattern 51a is formed on the glass substrate 51 for rendering the reflective film 52 uneven such that light coming from the required direction is reflected and undesired light reflection is reduced.
However, in the reflective liquid crystal display device having the above structure, the reflector 10 is provided outside the thick glass substrate 2, and thus, the incident light must be transmitted through the substrate 2 after passing through the liquid crystal layer 4. A parallal thereby occurs and disadvantageously results in a reduced contrast and a double image.
For forming the uneven pattern 11a on the glass substrate 51 of the reflector 10, the glass surface is treated with hydrofluoric acid to form an uneven pattern on the surface. However, according to such a technique, the shape of the fine uneven pattern cannot be satisfactorily controlled.
It is technically important to control the shape of the uneven pattern of the reflector because light in the required direction is thereby efficiently reflected and undesired light reflection is reduced.